The Stuarts ARE still technically on the throne, albeit through the Hanoverian line.
When Anne died in 1714, they looked for her nearest (Protestant) Stuart cousin, and that was George I of Hanover.
It is a popular misconception that the Hanoverians had no link to earlier monarchs and were a new family on the British throne.
Why ‘german george’?. Simple.
His grandmother was Princess Elizabeth, and she was a SCOTTISH and STUART princess, she was the daughter of King James VI of Scotland/James I of England, Wales and Ireland.
She had married the King Frederick of Hanover, so her offspring were Protestant Stuarts and therefore heirs to the British throne IF Anne died childless, which is what she did. The Dutch line of the Stuarts (1688-1714) died and the Hanoverians took over.
The other (no-go) option was a native Scottish/British king, but that would have meant a Catholic on the throne.
So today’s Royals sit on the throne because of their Scottish lineage, the notion they are 100% German usurpers is a nonsense.
They sit on the throne, again, because the Act of Secession in 1701 excluded Catholics from the throne. Without said act, the Electress Sophia of Hanover and her descendents would not have came to the English throne. Not only are the Stuarts higher up on the chain, so are all the older brothers and sisters of the Electress, something around 17 different branches.
“that would have meant a Catholic on the throne.”
The senior descendent from James VII/II are the Stuarts. Not the Hanoverians. The Hanoverians are a cadet branch.